Process for cracking oils



Dec. 29, 1931. LIJ. GARY PROCESS FOR CRACKING OILS 'Original Filed Oct. 21. 1920 Patented Dec. 29, 1931 UNITED STATES PATENT OFFICE LEE J. GARY, OF CHICAGO, ILLINOIS, ASSIGNOR TO UNIVERSAL OII PRODUCTS COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH. DAKOTA.

PROCESS FOR c mcxme" oILs Application filed October 21, 1920, Serial No. 418,432. Renewed November 23, 1928.

This invention relates to a process and apparatus for crackin oils, and has as its salient feature, the subJecting of the oil while in the cracking zone to successively decreasing pressures, while heated within the same furnace. The process may be operated either as a batch or continuous process.

In the drawing, the single figure shows a view partly in side elevation and partly in vertical section, of my improved apparatus.

Referring specifically to the drawing, 1 designates the furnace, 2 the burner, 3 the fire box and 4 the stack. In this furnace is mounted a plurality of superimposed shells 5, 6 and 7. The shell 5 may be, if desired, of somewhat smaller diameter than the shells 6 and 7, the latter two being of the same size. Each of the shells or stills is provided with a residue drawoif line 8, controlled by throttle valve 9. Oil is introduced into the lower shell 5 through charging line 10 having throttle valve 11 and connected to a feed pump 12. The still 5 is connected near its upper end to the lower end of the next still 6 by means of a transfer line 13 in which is interposed a throttle valve 14. The upper part of the still 6 is in turn connected by transfer line 15 in which is interposed a throttle valve 16 to the lower end of the top still 7. The upper end of the still 7 is in turn connected by transfer line 17 having throttle valve 18 to an expansion or vaporchamber 19 located outside of the fire zone. This vapor chamber 19 is provided with a residue drawofi' 20 having throttle valve 21 and with a vapor outlet pipe 22 having throttle valve 23. The pipe 22 is connected to the condenser coil 24 seated in condenser box 25. The lower end of this coil is connected by pipe 26 to the upper ed of receiver 27. This receiver 27 is provided with liquid level gauge 28, pressure gauge 29. It also has a liquid drawofi' pipe 30 controlled by throttle valve 31 and gas outlet 32 controlled by throttle valve 33.

The process may be operated as follows: Oil, as for example, 32 degrees Baum gravity Kansas gas oil, may be fed into the lower still 5 and thence overflow into the stills 6 and 7, until the two bottom stills 5 and 6 are full and the still 7 practically full or nearly so. The

oil may be heated to a temperature of say, 750

degs'. F., in the furnace, which may be indicated' by any conventional form of thermometer suitable for use in high pressure stills. By suitably regulating the valves shown, a pressure of 135 pounds may be maintained on the lowest still 5, 100 pounds on the still 6 and 75 pounds on the still 7. It will be understood that suitable pressure gauges, such as employed on the receiver 27, may be used for indicating the pressures in the various stills. This pressure of 75 pounds may be maintained on the balance of the system. By continuously feeding the oil in, the lower stills at all times will be maintained full of oil and the still 7 in the same condition so that oil in the liquid phase is delivered to the vapor chamber.

The process may also be carried out as follows: The still 5 may be maintained, say three-fourths full of oil and only the vapors pass into the upper stills. In this case, the

vapors will be superheated but at a reduced pressure, in still 6 and a still further reduced pressure in still 7. The same different pressures may be obtained as in the process first described.

As a still further manner of carrying out the process, the still 5 may be charged in the manner last described and'a pressure of 300v pounds may be maintained on the lowest still, 200 pounds on the middle still and 100 pounds'on the upper still, 75 pounds on the vapor chamber and pounds on the water condenser and receiver.

It is to be understood that I do not limit myself to any particular differential pressures. The oil may be delivered in vapor form to the vapor chamber or in liquid phase. If delivered in liquid phase, this of course, is a different method. What I claim as new is the heating of oil in the furnace, and as part of a continuous process, subjecting it to differential pressures in the heating zone.

I claim as my invention:

1. A process of cracking petroleum, comprising subjecting said oil to the action of heat and superatmospheric pressure, by causing the oil to pass in succession through a plurality of separate interconnected heatdensing the vapors.

ing elements maintained at cracking temperature, maintaining a predetermined superatmospheric pressure on the initial heating element, in reducing the pressure in successive heating elements, causing all the oil charged to the initial heating element during operation to traverse successively through the .heating elements, Withdrawing the heated oil from the last element and passing same to a vaporizing zone where substantial separation of vapors takes place, and con- 2. A process of cracking petroleum, comprising subjecting said oil to the action of heat and superatmospheric pressure, by causing the oil .to pass in succession through a plurality of separate interconnected heating elements maintained at cracking temperature, maintaining a predetermined superatmospheric pressure on the initial heating element; in reducing the pressure in the last heating element below the pressure maintained in'the initial heating element, causing all the oil charged to the initial heating element during operation to traverse successively through the heating elements, with-- drawing the heated oil from the last element and passing same to a vaporizing zone Where substantial separation of vapors takes place,

and condensing the vapors.

3. A process of cracking hydrocarbon oil for the production of lower boiling point hydrocarbons from higher boiling point hydrocarbons which comprises subjecting the oil to the action of cracking conditions of temperature and pressure by causing the oil to pass in succession through a plurality of separate interconnected heating elements, maina taining a predetermined superatmospheric pressure on the initial heating element and partially vaporizing theoil therein, passing only evolved vapors fromflthe initial heating element to the succeeding heating elements wherein said vapors are superheated in the absence of liquid oil, reducing the pressure in saidsucceeding heating elements,

passing the superheatedvapors from the last heating element to an enlarged zone, remov- 1n the vapors from said enlarged zone and su jecting the same to condensation.

LEE J. GARY. 

